Wave-type linear motion mechanisms generally comprise a rigid screw member formed with a female screw, a flexible screw member that can flex in the radial direction and is formed with a male screw, and a wave generator that has an elliptical contour and serves to create a state in which the flexible screw member is flexed into an elliptical shape and made to partially mesh with the rigid screw member at positions on the major axis of the elliptical shape. The leads of the female screw of the rigid screw member and the male screw of the flexible screw member are different. When the wave generator rotates, the meshing positions of both move in the circumferential direction, and relative linear motion is generated between the two in the axial direction. If one of the members is immobilized, the other member moves linearly in the axial direction, and members that are connected to that member can be, e.g., positioned in the axial direction. Wave-type linear motion mechanisms having this configuration are disclosed in Patent Document 1 (Japanese Utility Model Publication No. 6-38195) and Patent Document 2 (Japanese Patent Laid-Open No. 2007-154955).